Harper's promotion makes sense for two reasons: First, with Zimmerman sidelined, the Nationals are without their usual No. 3 hitter and could use a boost to their offense. Second -- and somewhat related to the first point -- the Nationals have received a collective .097 batting average and .332 OPS from their left fielders thus far; no team has gotten a lower batting average from a single non-pitching defensive position, and only the Oakland Athletics' third basemen have a lower OPS (.313). In fact, 10 teams have gotten higher batting averages from their pitchers.

Still, fantasy owners shouldn't buy in -- at least not at a steep price.

Harper might be a future superstar, a potential multiple-MVP award winner during his prime and a good keeper-league prospect. He is still, however, 19 years old today, and his statistical performance this calendar year hasn't been great.

In nine spring training games, for example, Harper batted .286/.333/.357 (BA/OBP/SLG), including 11 strikeouts in 28 at-bats. And in 20 games for Triple-A Syracuse, he has hit .250/.333/.375 with 14 K's in 72 at-bats. Sum his statistics between the spring and Triple-A, and Harper is a .260 hitter with one home run in 100 at-bats. A left-handed hitter, Harper also has struggled against left-handed pitching; he was 4-for-21 (.190) with six K's and zero home runs against them for Syracuse. There is a chance that, for this season at least, he might be no more than a .260-batting, 18-homer hitter, and that assumes at least 150 games played.

The list of historical standouts at the age of 19, too, is short. The record for home runs by a 19-year-old is 24, set by Tony Conigliaro in 1964. Only five players in history have had even a 10-homer season at the age of 19. And if you're looking for perhaps the all-time best season by a 19-year-old, that probably would belong to Mel Ott, who managed .322/.397/.524 triple-slash rates, 18 home runs and 77 RBIs in 124 games in 1928, or 84 years ago.

What Harper is being asked to do is monumental, and there's not even a guarantee he'll be up with the Nationals permanently. Early struggles could earn him additional seasoning in the minors, Zimmerman's return could do the same and there's that "arbitration clock" timetable to consider, being that most teams concerned about that usually keep prospects in the minors until at least June.

A "steep price" could be considered a No. 1 waiver position or a more productive hitter -- almost anyone actually ranked on Wednesday's Hit Parade top 125 qualifies -- so while Harper absolutely warrants a speculative pickup in any format if you have the room, make sure you have the room.

Bumping Xavier Nady for Harper, as the Nationals appear set to do, makes sense in fantasy. (The Nationals might now use Nady, Rick Ankiel and Roger Bernadina in a three-man rotation in one outfield spot, with Jayson Werth shuffling between right and center field to accommodate them.)

Bumping Werth himself, or even a lesser outfielder such as Logan Morrison, does not make sense.

A Los Angeles team announced a closer change Friday, and it was not the Los Angeles Dodgers, who have absorbed three losses and two blown saves from their finisher, Javy Guerra, in his past five appearances. No, it was the Los Angeles Angels, who announced a temporary demotion for Jordan Walden, a day after he blew a save and took the loss Thursday at Tampa Bay.

Walden's removal is somewhat puzzling, being that he began the season as the Angels' clear closer and now loses his job following only his second poor outing in six appearances thus far. Coming off a 2011 season during which he led the majors in blown saves (10), Walden suffers from an apparent short leash by the Angels, which is especially troublesome considering how well his replacement, Scott Downs, has pitched since the middle of last season.

Since last July 1, Downs has a 0.81 ERA, a 1.11 WHIP and 18 holds in 37 appearances, numbers that should rank him atop your pickups list. Formerly a top source of holds, he's now as good a bet for saves as there is in the game so long as he keeps the job for an extended period. Walden might be the Angels' future in the ninth inning, but Downs has outpitched him the past year-plus; if they keep up their respective levels of performance, Downs might never give the job back.